This invention relates to a process for the production of custom-moulded ear-plug devices.
The invention addresses problems primarily encountered in the fabrication of in-ear hearing aids. However, the solution offered is equally implementable in the manufacture of all types of custom-moulded ear-plug devices intended for application and use in areas of dynamic movementxe2x80x94as will be discussed further below.
In applying the currently predominant method of producing in-ear hearing aids, an audiologist takes an impression of the ear canal of the person concerned and sends that to a hearing-aid manufacturer who fabricates the hearing-aid shell conforming to the said impression. Based on the diagnostic data, also established by the audiologist, the customized hearing-aid shell for the individual""s specific hearing aid is assembled together with the appropriate electronic modules.
It is of paramount importance, especially in view of the relatively rigid materials currently employed in producing hearing-aid shells, that the outer contours of the hearing aid precisely match the auditory meatus of the person concerned. This usually required additional fitting sessions and a fine-tuning of the outer contour of the hearing aid.
Notwithstanding all the efforts aimed at optimizing the wearing comfort of the hearing aid, this approach cannot take into account the dynamic movement of the auditory canal for instance during mastication, given that the impression taken is at best a snapshot of the ear-canal configuration in a particular position of the person""s jaw.
It is the objective of this invention to introduce a process of the type first above referred to, designed to solve the aforementioned problem. To that end, the idea is to record a three-dimensional image of the area of application at a minimum of two points along its dynamic movement and to use the data recorded for optimizing the design of the custom-moulded ear-plug unit for the area of application that is subject to movement.
In applying this process, in its simplest although not necessarily least expensive form, for producing an in-ear custom-moulded ear-plug device of in-ear hearing aid, at least two impressions are taken of the ear canal, and preferably more than two such impressions in different positions of the jaw, and thus of the ear canal, during mastication. With the aid of the data registered the custom-moulded ear-plug shell, for now assumed to be rigid, is formed in such fashion that during mastication any discomfort is minimized while still maintaining its position within the ear canal, i.e. the area of application. In another form of implementation of the process per this invention, the data recorded serve to optimize the design of the custom-moulded ear-plug unit in terms of its physical properties, i.e. its flexibility and compressibility.
The optimization procedure is preferably based on computer modeling. The digitized three-dimensional data corresponding to the model found to be optimal are then used to control the subsequent fabrication process especially in shaping the shell.
However, rather than employing the time-consuming method of producing multiple impressions of the area of application, that being the ear canal or auditory meatus in the case of in-ear custom-moulded ear-plugs, it is proposed that the dynamic movement of the area of application be imaged using more than two frames, somewhat similar to a film strip, for instance by means of x-rays or in-ear video pictures.
As stated, a preferred form of implementation of the process per this invention involves the imaging of the area of application in more than two positions, meaning multiple positions, so as to cover to the maximum extent possible the entire daily dynamic range of the area of application. In one implementation of the process per this invention, the captured data serve to optimize the outer contour of the custom-moulded ear-plug unit in the non-moving state. As mentioned above, this applies especially when relatively rigid custom-moulded ear-plug shell materials are used, or for the base position prior to further optimization allowing for flexible or compressible sections to be designed into the custom-moulded ear-plug device. Accordingly, it is further proposed that the data acquisition serves to optimize the physical properties of the custom-moulded ear-plug unit by determining where and how the custom-moulded ear-plug unit and especially, if built-in modules are to be provided, its shell is to be made flexible or compressible.
In a preferred form of implementation of the process of this invention, further optimization of the custom-moulded ear-plug design is obtained by digital imaging and the computer-aided design found to be optimal is used to control the fabrication of the custom-moulded ear-plug unit. The process per this invention is particularly well suited to the production of in-ear custom-moulded ear-plugs, especially in-ear hearing aids, but also of headphones as well as ear protectors such as noise- or water-blocking ear plugs. However, it is also entirely suitable for the precise fitting of outer-ear custom-moulded ear-plugs and especially of pinnal hearing aids.